Rotary engine



(No-Modem 3 Sheets-Sheet 1.

J. V. DAVIS. ROTARY ENGINE'.

No. 516,431. Patented Man-13, 1894A.

(No Model.) 3 Sheets-Sheet 2.

J. V; DAVIS.

ROTARY ENGINE. 1

-v1\T0. 516,43l. E Patented Mar. 13, 1894.

y fm? Zzzess es: v Inventor.'

Ja/m www@ (No Model.) 3 Sheets-Sheet 3. J.V. DAVIS. `ROTARY ENGINE.

mi Norms Uses cn. Novo-urna, msummom u c.

- UNITED STATES PATENi` OFFICE.

JOHN VINCENT DAVIS, OF NEW YORK, N. Y., ASSIGN OR TO THE CHALLENGE llIGI-I SPEED ENGINE COMPANY, OF lLEXINGT ON, KENTUCKY.

ROTARY ENCBINE.V

SPECIFICATION forming part of Letters Patent No. 516,431, dated March 18, 1894.

Application led Tune 13, 1893- Serial No. 477,417. (No model.)

.To all whom, it may concern.-

Be it known .that I, JOHN VINCENT DAVIS, of New York, in the countyof New York and State of New York, have invented certain new and useful Improvements in Rotary Engines, Concentric Pistons; and I- do hereby declare that the following isa full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the let- `1o ters of reference marked thereon, which form part of this specification.

This invention is an improvement in rotary engines of the concentric piston type, and its object is to produce an automatic cutt5 0E, direct acting, rotary engine, in which the pressure of live steam on the operativeparts will be perfectly balanced, and lateral thrust on the main shaft be obviated, by making the steam balance the piston on the shaft at zo the same .time that it acts to rotate the piston and shaft.

Another object is to prevent a substantially uniform amount of abutmentsurfacefor the steam to act against in driving the piston;

and another object is to provide novel valve mechanism for directly controlling the admission aud emission ot' steam from the piston chamber or cylinder.

My improved engine has an undulating sur- 3o faced piston formed with an unequal number of longitudinal alternating lobes or projections and intermediate depressions. Vlhe piston is so formed that its diameters are equal, taken through its axis from any point, the

3 5 depressions gradually merging into the lobes'l It also has an or projections and vice versa. equal number of abutment valves, exactly twice as many as there are lobes on the piston, or one for each lobe and each depression 4c on the piston, and these abutment valves are arranged at equal distance apart radially of and exterior to the piston.A The diametrically opposite abutment valves are connected together at their ends, and owing to the shape of the piston, one ot' the valves in a pair will be opposite a depression in the piston, when the other is opposite a lobe, and vice versaat all times. The inner edges of the abutment valves fit neatly against the pistou, and as the diametrically opposite valves are con- 5o nected they are both kept in proper contact with the surface of the piston, as the latter acts as a cam, and when one valve is forced outward bya lobe of the piston moving therepast, the opposite valve is drawn inward in to the depression in the valve diametrically opposite such lobe. The piston is thus made to actuate the abutment valves Without the employment of springs, steam pressure, cams, or' other auxiliary means, and each abutment 6o valve actuates the diametrically opposite abutment valve and is in turn shifted thereby. The pistonis axially centered in a cylinder whose interior diameter is such that its outermost portions of thelobes itclosely against the inner wall of the cylinder, so that a series of longitudinal chambers are formed in th-e cylinder between the lobes of the piston. Ql'hese chambers are again longitudinally divided by alternate abutment valves. These 7c. abutment valves are non-rotatable and play through longitudinal slots in the cylinder, being housed in', so that steam cannot escape from the cylinder through theslots,aud suitable packiugs may be employed at the joints ofthe housings and cylinder and on the sides l and inner edges of the abutment valves to prevent leakage of steam. 1t will be understood however that the steam chambers above mentioned are not constant in position-be 8o cause the'piston rotates and the abutment valves in succession divide the chambers.

In operating the engine, steam is admitted between every alternate pair -of abutment valves, and simultaneously exhausted between every other alternate pair of abutment valves, the steam inlet and exhaust ports being at opposite cnds of the engine. In other words steam is admitted at one side of each abutment valve occupying' a depression of 9o the pistou, and simultaneously exhausted at the opposite sides ot such valves, consequently the steam expanding between the cylinder, abutmcnt valves, and lobes ofthe piston will cause the piston to rotate sulliciently l to move the lobes past the abutment valves which were on top thereof when the engine started, and then the steam is admitted between such valves and the lobes, and as soon i main engine shaft and `rotates with the pisas the pressure of steam between and against anytwo adjoining abutment valves is equalized, the inl't valve is closed and the outlet port opened, thus in an engine having ath ree lobed piston, and six abutment valves,l first admit steam at three or more equidistant points simdltaneously, and exhaust steam at three or more intermediate equidistant points, and then exhaust steam at the first three points, and admit it at the latter three points during each complete revolution of the piston, and so on during the operation of the engine. The piston in such engine thus has three impulses given it for each revolution. The steam being admitted at three or more equidistant points, it will be obvious that the radial pressure of the steam in the ehamf bers upon the shaft or axis of the piston is mutually counteracted, and consequently lateral thrust of the shaft or piston is prevented, and there is no wear on the journals produced by such radial pressure. This radial pressure is one of the great `defects in ordinary rotary engines wherein the steam is alternately admitted at oppcsiteysides of the piston, as the radial pressure of steam on one eide of the piston not being connteracted by an equal pressure on other sides, or equi-distant points, has to be borne by the piston journals, or main shalt, and thus excessive .wear is engendered, and the piston soon be girls to Wabble, and the engine always jars and trembles in action. `This is especially true of rotary engines cmployingeccentric arranged pistons.7 In my engine these defects are obviated and the piston is actually connterbalanced and floated by the workin g steam pressure in the cylinder. lt will be Linderstood. that when steam is working against one valve, it is exhausting in front ci' the connected diametrically opposite valve. As the piston turns however, this connected valve is moved inward at the same speed and to the same extent that the first'valve is moved out- Ward,and as soon as the lobe has moved past the inlet port beside the second valve, steam is admitted thereagainst; thus the amount of abutment valve surface against which the live steam is working is substantially maintained at all times, as the amount of abutn ment surface presented by one of each pair of diametrically opposite valves is increased in the exact ratio that the amount ot' abutment surface presented by the other ot' such valves is diminished, and vice versa. In my engine I employ a novel valve mechanism composed of three disks; the outer and inner disks have a series of equi-distant slots corI responding in number to the abutment valves of the engine, and the slots ot the inner disk communicate with ports leading through the cylinder walls beside the respective abutment valves. many equidistant perfcrations 1n 1t as the other disks have slots and it is xed on the The intermediate disk has half as ton, while the outer and inner disks are fixed, :or non-rotatable. These disks are inclosed in a steam chest on the end of the cylinder in such manner that no steam can enter the` cylinder ports except through the openings in the disks. The slots in the outer and inner disks coincide and when' the openings in the intermediate disks coincide with the slots in the other disks steam can enter the cylinder. As there are only half as many perforations in the intermediate disk as there are slots in the other' disks it will be obvious that steam will enter the cylinder only through every other port, at one time, but that all the ports will be opened once during the revclu tionn of the piston. The same valve mechanism can be used for the inlet and exhaust ports, by applying a set of the disks at opposite ends of the engine. In order toregulate the admission of steam to the engine the inner disk maybe made slightlyrotatable so that it can be partially turned so as to vary the register of its slots with those of the outer diskg and consequently the length0f time when the perforations of the inner disk coincide with the slots in the inner and outer disks. A governor can be used to control the position of the inner disk, and thus the supply of steam be automatically controlled by the speed of the engine.

The accompanying drawings illustrate a good form oit' working engine and the valve mechanism, and referring thereto by letters of reference for a more detailed description of my invention, Figure l represents a perspective view of the complete engine. iongitudinalverticalsectionthroughthesame; Fig. a detail longitudinal section showing the valve ports. Fig.. 3 is a face view of the valve mechanism partly in section. Fig. l is an end view ofthe cylinder with head removed showinginterior parts. Fig, isa perspective vievvoi an abutment valve. Fig. 6 is a detail View of the inner face r3E one of the valves. Figs. 7 and S are detacl el views of the valve disks. f

l have illustrated au engine having a three lobed piston, and consequently six abutnicnt valves1 A designates a cylinder mounted on a suitable base.

l5., B, are the cylinder headsrigidly secured to the ends oi?` the cylinder, each having an annular chamber h on their exterior faces in which are fitted 'the valve disks, and a centrai opening for the passage of the main shaft C. The chambers b are closed by removable plates D which are provided with stufling boxes cl/in which shaft C is journaled. The piston E is roughly trefoil-shaped, having three lobes e and three intermediate depressions e'.

y F, l?, designate the abutment valves, six I in number arranged at equi-distant points l around the piston, and playing through lon- Fig. 2 is a IIO agitudinal slots in the cylinder and protected" by housings F attached to the cylinder as shown. Each pair of diametrically opposite valves are rigidly united by means of bars f which are fastened to the ends of the valves and work in radial grooves b in the inner faces of heads B, and a're slotted as at f for the passage of shaft C, and to permit the 1ongitndinal movement of the bars. These bars cause the opposite valves to alternately and simultaneously move in and out, as the piston rotates, the surface of the piston acting as a camto move the valves. At one side of each abutment valve, a longitudinal inletport G is made in the walls of the cylinder, said port being Yclosed at one end, but communicates at the other end with one of the ports g in one head B. At the opposite side of each abutment valve is a similar exit port H, closed at the-end adjoining ports g, but communicating at the other end with one of the exit ports h in the opposite head B. The inlet valve consists of three annular disks J, K, L; disk J is centered on the end of shaft C within chamber b, and is provided with six transverse equi-distant slots j, adapted to register with ports g. This disk does not turn with the shaft C. The disk K is similar in size to disk J, but has a hub lo by which it is splined on shaft C as shown. It also has butl three openings la much smaller than ,the slots Z. Disk L is similar to disk J, having six slots Z, and is mounted on the hub of disk K but is kept from rotating by a set screw L tapped through the wall of the chamber as shown. Only disk Kv rotates, and it revolves with the piston; consequently as it rotates, its openings k register with three alternate slots j, and Z,'alter nately. When the openings in disks J, K,\L, register, steam is admitted into the cylinder and the engine is operated, as above described.

The exhaustvalve mechanismis constructed like the inlet valve, but the intermediate disk K thereof is fixed on shaft C so that its openings stand intermediate the openings ih the disk K of the inlet valve mechanism, consequently steam will be exhausted from one side of the abutment valves simultaneously with its admission at the other side thereof, or in other Words, steam will be admit-ted between alternate pairs of abutment'valves, and simultaneously exhausted between the' intermediate alternate pairs of abutment valves, as indicated by the arrows in Fig. 4.

It will] be clear from the foregoing description that the simple rotation of one valve disk controls the admission of steam into the cylinder at six equi-distant points, during one rotation of the piston, and that steam is admitted at but three equi-distant points at one time. The piston therefor-e is continually balanced, and lateral thrust of the main shaft is prevented. Steam is admitted to and exhau'sted from the opposite chambers b, b, by

pipes S, s.

In order to automatically regulate the admission of steam into the engine, the disk of the inlet valve mechanism is made partly rotatable, and is provided with a segmental rack J at a convenient point of its periphery. This rack ,is meshed by a small pinion m o-n the inner end of a stub shaft M journaledin the head and plate as indicated fn the drawings, and a small pinion m is fixed on the outer end of said shaft, and is meshed-by a. segmental rack 'N pivoted on a suitable support and connected in any suitable manner with a governor 'n which is driven from the main shaft.

The construction of the governor and of connections between it and shaft M and main shaft, whereby it is caused to rock shaft M is not ofthe essence of the invention, and may be of any suitable construction. As shown, the governor tends to rock shaft M when the speed reaches the Amaximum point, and by so doing it causes the slight rotation of disk J, and consequently alters the position of its slots with relation to those in disk L, and consequently the length of time when the perforation in disk k will register simultaneously with slots in disks L and J is shortened, and the supply of steam to the engine diminished. Thus in a simple and eifective manner I provide an automatic cut-o for the engine and am enabled to perfectly control it. By using similar valve mechanism for the inlet and outlet ports I can reverse the engine by admitting steam at the exhaust side and exhausting it from the inlet side. shaped, having the slots and perforations in their rims, and as steam can pass freely between the spokes thereof there is very little frictionalcontact surface between the disks. The piston may have a greater but unequal n'umber of lobes, and must be of equal diam ete-r in any cross section through its axis. The engine must have an equal number of abutment Valves in order that the diametri- The 'disks J, K, L, are really wheel- IOO IIC

cally opposite valves may be connect-ed and operated as above described.

When it is not desired to .make the engine reversible, the outlet valve mechanism may be modified, by making disk J fast to the head, or by omitting said disk and dressing the bottom of chamber b and the ends of the cylinder ports so that the latter correspond to the slots in disk J, and disk K works APatent thereon, is-

formed Withan odd'number of longitudinal lobes, in combination with a series of equidistant abutment valves arranged in diame' trically opposite pairs, one pair for each lobe of the piston, the opposite valves in each pair being rigidly united so as to move synchronously, and opcratedonly by their direct contact with the piston and connection to each other, substantially as described.

2. In a rotary engine the combination of the cylinder, a piston having an odd number ot" longitudinal lobes, and similar number ot intermediate depressions, and a series of abutment valves, one for each lobe and depression of the piston, with means for admitting steam at one side of three or more alternate valves at atime, until all the valves haye been inv active work once during each revolu tion of the piston, substantially as described.

3. The combination of the cylinder and piston therein, and abutment valves; With the inlet ports beside each valve, and -valve mechanism substantially as described for admitting steam successively into alternate ports, and to three or more such ports at a Atime, substantially as described.

et. In a rotary engine the combination of 'the cylinder, a piston having an odd number of longitudinal lobes, and similar number ot intermediate depressions, and a series of abutment valves, one for each lobe and depression of the piston, with means for admitting steam at one side of three or more alternate valves at a time, until all the valves have been in active Work once during each revolution of the piston, and means for si multaneously exhausting steam at one side of such valves simultaneously with the admission of steam against the other side, substantially as described;

5. A rotary steam engine having a concentric piston of equal diameter throughout formed with an odd number of longitudinal lobes, in combination with a series of equi` distant abutment valves arranged in diametricaily opposite pairs, one pair for each lobe of the piston, the opposite valves in each pair beingV rigidly united so as to move synchronously, and operated only by their direct contactwith the piston and connection to eachdther, and mechanism for admitting steam against one valve of each pair, and exhausting it in front of the opposite valve, substantially as and for the purpose specified.

6. The combination of the cylinder, the series of 'radial abutment valves, the outlet and inlet ports at each side of each abutment valve, and the piston having an odd number of lobes and depressions the sum of which equals the number of abutment valves, and valve mechanism whereby steam is admitted successively into alternate inlet ports; and to three or more such ports at a time substantially as described.

7. The combination of the piston having an' odd number of lobes but of equal diameter in cross section throughout; with the cylinder,

erase-i the cylinder heads, the abutment valves arranged in diametrically opposite pairs, one

pair for each lobe on the cylinder, and thel valvels in each .pair beingl connected together so as to move synchronously; with inlet and eXhau st ports on opposite sides of each abutment valve, and mechanism substantially as Ation adapted to intermittently register with those of the outer and inner disks, the outer and inner disksbeing non-rotatable, While the intermediate disk rotates, substantially as described.

9. The combination of an engine cylinder having an even number of inlet ports, with a rotating disk having half as many openings adapted to simultaneously register with alter nate ports, substantially as and for the .purpose described.

l0.y The combination in the rotary engine of the cylinder having an' even number of equi-distant ports, and a piston therein; with a rotating disle adapted to revolve synchronously with the piston provided with equi-distant openings adapted to simultaneously register with th re or more alternate cylinder ports, and to register With all the cylinder ports once dnrin g each revolution thereof substantially as described.

1l. The combination ot the cylinder, its equi-distaut inlet ports, the rotating piston, the disk mounted on the piston shaft having equi-distant openings adapted to register with three or more alternate cylinder ports simultaneously, and diametrically opposite abutment valves intermediate the cylinder ports,the opposite valves being connected substantially as described.

l2. The combination of the cylinder, its inlet ports and the piston and main shaft; with the valve mechanism consisting of three disks,

the inner and outermost disks being stationary having corresponding slots equal in nnnr ber to the ports of the cylinder, and the slotsy of the inner disk communicating with said` ports, and an intermediate rotating disk hav-l ing openings adapted to register with alternate openings in the other disks, and mechanisni whereby the inner disk may be slightly rotated so as to vary the length of register between the openings in the intermediate disk and the slots in the outer and inner disks, substantially as described.

, number of lobes, the diametrically opposite IIO but connected abutment valves, one pair for In testimony that I claim. the foregoing as each lobe of the cylinder, the inlet and outmy ownI aix my signature 1n presence of two leb ports on opposite sides of each abutment witnesses.

Valve, and the chambered Vcylinder heads, JOHN VINCENT DAVIS. wit-h the valve mechanisms in the chambers Witnesses: of said heads, constructed and operated sub-. AUGUSTA TILESTON,

Siantially as herein shown and described. f C. W. MERRIAM. 

